Flawed Fracking Wells Taint Pennsylvania's Drinking Water

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Fetid, flammable, polluted drinking water in Pennsylvania homes
near natural gas drilling sites was contaminated by methane
escaping from flawed fracking wells, a new study shows.

Based on geochemical forensics work, the research makes a direct
link between tainted drinking water and leaky gas wells in the
Marcellus Shale. The rock layer is thousands of feet
below the surface, but the leaks are shallow, where cement and
steel are supposed to shield water supplies from natural gas
inside wells. Scientists saw the same connection in Texas, above
the Barnett Shale, they report today (Sept. 15) in the journal
Proceedings of the National Academy of Sciences.

"This does provide pretty strong evidence that it's a well
integrity problem and not a fracking problem," said lead study
author Tom Darrah, a geochemist at The Ohio State University in
Columbus.

The energy industry has contested claims that fracking
can contaminate water supplies. Fracking is the process of
shattering deeply buried rock to release trapped natural gas. Oil
and gas companies have claimed that drinking water pollution may
be caused by methane gas slowly bubbling up naturally through
cracks in rock layers. Other groups have debated whether the
methane came from fracking, horizontal drilling or leaking wells.
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In the study, researchers traced methane gas in more than 130
Pennsylvania and Texas water wells to poorly sealed, cracked or
failing fracking wells. Several layers of cement and steel
typically protect shallow underground water supplies from gas and
fluids pulsing through fracking wells. The thickest layers are at
the top, to create a buffer between the well and groundwater. The
wells narrow with depth, similar in shape to a telescope.

Both the cement and steel casings can fail because of damage
during installation, corrosion, design flaws or age — known as
"well integrity problems."
Methane gas will escape through any openings.

The discovery means there is hope for Pennsylvania's polluted
drinking water, Darrah said. Fixing existing wells and keeping a
sharp eye on new drilling sites could reduce contamination.

"There's actually a little bit of good news," Darrah told Live
Science. "If we improve well integrity, we can eliminate a lot of
the environmental problems that have surrounded fracking so far,"
he said.

Widespread effects

About 6 percent of Pennsylvania's fracking wells have documented
well leaks, according to a June 30, 2014, study by engineering
professor Anthony Ingraffea of Cornell University in Ithaca, New
York. Up to 100,000 new fracking wells could be drilled in
Pennsylvania in the next few decades.

But methane isn't the only
contaminant in drinking water wells near natural gas fracking
sites. Dangerous levels of arsenic and
barium have also been found. Salty natural brines from deep rock
layers are also migrating upward toward the surface. An
Environmental Protection Agency review of nationwide well safety
and fracking's effects on water supplies is due this year.

The boom in fracking (or hydraulic fracturing) has boosted U.S.
natural-gas production by 30 percent in the past decade. The
drilling has also sparked an
increase in moderate earthquakes in states such as Oklahoma,
Arkansas and New Mexico, as well as fears of widespread
environmental contamination. Leaking wells also emit methane into
the atmosphere, where the greenhouse
gas is about 34 times more efficient at trapping infrared
radiation (the greenhouse effect) than carbon dioxide, though
methane breaks down much more quickly than CO2.

Measuring methane

Darrah said multiple lines of evidence confirm the methane leaks
come from the Marcellus and Barnett shales, or from shallower
methane pockets in overlying rocks. Carbon isotopes revealed the
methane was created by heat and pressure, not from microbes in
groundwater. (Isotopes are versions of the same element with
different numbers of neutrons in their nuclei.)

Trace amounts of noble gases helped determine how fast the gas
bubbled into drinking water supplies. Naturally rising methane
should have about 10,000 times more helium than the gas polluting
the drinking water wells, Darrah said. But the helium, neon and
argon suggest the methane zipped to the surface via a fracking
well, and then leaked out into groundwater.

"Somehow, these gases managed to get to the surface without going
through any water or rock, and in some cases, we could actually
document well integrity was the problem," Darrah said.